This invention relates generally to waste heat recovery systems and, more particularly, to an organic rankine cycle system for extracting heat from a reciprocating engine.
Power generation systems that provide low cost energy with minimum environmental impact, and which can be readily integrated into the existing power grids or which can be quickly established as stand alone units, can be very useful in solving critical power needs. Reciprocating engines are the most common and most technically mature of these distributed energy resources in the 0.5 to 5 MWe range. These engines can generate electricity at low cost with efficiencies of 25% to 40% using commonly available fuels such as gasoline, natural gas or diesel fuel. However, atmospheric emissions such as nitrous oxides (NOx) and particulates can be an issue with reciprocating engines. One way to improve the efficiency of combustion engines without increasing the output of emissions is to apply a bottoming cycle (i.e. an organic rankine cycle or ORC). Bottoming cycles use waste heat from such an engine and convert that thermal energy into electricity.
Most bottoming cycles applied to reciprocating engines extract only the waste heat released through the reciprocating engine exhaust. However, commercial engines reject a large percentage of their waste heat through intake after-coolers, coolant jacket radiators, and oil coolers. Accordingly, it is desirable to apply an organic rankine bottoming cycle which is configured to efficiently recover the waste heat from several sources in a reciprocating engine system.
It is therefore an object of the present invention to provide an improved ORC waste heat recovery system.
Another object of the present invention is the provision for extracting waste heat from a number of sources from a reciprocating engine.
Yet another object of the present invention is the provision for employing an ORC for recouping waste heat from a reciprocating engine.
Still another object of the present invention is the provision for recovering waste heat from a number of sources of a reciprocating engine in an effective and economical manner.
These objects and other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.